This invention relates to folded sheets of paper tissue or similar material. More particularly, the invention relates to a balanced stack of interfolded sheets wherein removal of the top sheet moves the next sheet into position for removal.
Paper products such as sheets of tissues and towels are conventionally folded and superposed to form a stack which may be stored in a container or dispenser. It is desirable to interfold or interleave the sheets of the stack so that removing the top sheet from the container causes the next sheet to "pop-up" or move into position for removal. It is also desirable that the stack be balanced, i.e., have uniform bulk across its width. Any vertical cross section through the stack should have substantially the same number of layers of sheet material.
The folded sheets can be either wet or dry. Wet sheets are pre-moistened and present additional packaging considerations. The moisture creates additional friction as the interfolded sheets are withdrawn, and the portion of the sheet which extends out of the container is subject to drying. The exposed portion should therefore be relatively short.
U.S. Pat. No. 4,138,034 describes a package of pre-moistened interleaved sheets. The sheets may have alternating V folds, or alternating Z folds.
U.S. Pat. No. 3,401,928 describes a stack of interleaved sheets in which each sheet includes two quarter folds on the top and a half-width fold on the bottom (FIG. 9). Adjacent sheets are folded in opposite directions so that the stack is balanced.
U.S. Pat. No. 5,497,903 describes a stack which is essentially an inversion of the stack of the '928 patent.